Question: Subtract.
There are many ways to solve this problem. Let's see two ways we can solve it. Place Value We can think in terms of tenths: $\begin{aligned} &\phantom{=}18.5 -14.3\\\\ &=185\text{ tenths} - 143\text{ tenths}\\\\ &=42\text{ tenths}\\\\ &=4.2 \end{aligned}$ Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths $1$ ${8}$ $.$ ${5}$ $1$ $4$ $.$ ${3}$ Now, let's subtract each place value column. Tens Ones $.$ Tenths ${1}$ ${8}$ $.$ ${5}$ $-$ $1$ ${4}$ $.$ ${3}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $0$ $4$ $.$ $2$ $4.2 = 18.5 - 14.3$